This invention relates to cross-linkable vinyl ester and/or vinyl halide copolymers containing hydroxyl groups, which copolymers are cross-linkable through the hydroxyl groups.
Copolymers of vinyl esters and/or vinyl halides containing monomer units carrying hydroxyl groups, which may also contain other copolymerizable monomer units, are known. The monomer units carrying hydroxyl groups which are presently available are those which are obtained by saponification of vinyl chloride/vinyl acetate copolymers or which can be obtained by polymerization of hydroxyl group-carrying monomer units. Presently employed as monomer units carrying hydroxyl groups are, for example, monomers, such as hydroxyalkyl vinyl ethers, dihydroxyalkyl maleates and hydroxyalkyl acrylates or methacrylates. The disadvantage of these hydroxyl group-carrying monomers is that on copolymerization an unfavorable distribution of these units in the polymer results so that the cross-linkage with diisocyanates is either incomplete or requires an uneconomically high hydroxyl group concentrations for the cross-linkage.
Allyl esters of hydroxycarboxylic acids, such as allyl glycolate, allyl lactate, have likewise been employed as monomer units containing hydroxyl groups, but these allyl esters of hydroxycarboxylic acid monomers act as regulators or chain transfer agents in the polymerization and, beyond that, reduce the rate of polymerization.